Question

Two separate bulbs of equal volume contain ideal gases $A$ and $B$ respectively. The density of $A$ is twice the density of $B$ and molecular weight of $A$ is half the molecular weight of $B$. If the two gases are at the same temperature, the ratio of the pressures $\left(\frac{P_A}{P_B}\right)$ of the two gases is:

• A. $1$
• B. $\frac{1}{4}$
• C. $\frac{1}{2}$
• D. $4$

Answer 1

Answer: (D)

$4$

$d=\frac{PM}{RT}{d}_A=2d_B{M}_A=0.5M_B\frac{P_A{\times 0.5M}_b}{RT}=2\frac{P_B{XM}_b}{RT}\frac{P_A}{P_B}=4$